Trench 3, at the north end of St Nicholas’ Street, was dug deeper than most of the other trenches in order to gain access to a mains junction. The middle of the trench was approximately 2.15m deep. Natural sand was possibly seen on the western side of the trench at a depth of 1.8m.

A large Roman wall foundation, constructed of septaria blocks with occasional fragments of Roman brick and tile set in a hard pale brown mortar, was observed in the north-eastern part of the trench at a depth of between 1.4m and 1.95m. It was not possible to examine this feature in detail and recording had to be done from street level. The large size of this foundation indicates that it could have belonged to the projected public building in Insula 30, its position suggesting that while it was close to the western edge of the Insula, it was probably not on the street frontage. <1>